ML19331C892

From kanterella
Jump to navigation Jump to search
Responds to Re Mount St Helens & Power Plant. Technical Rept Which Discusses Possible Impact of Volcanic Activity on Plant Encl.Based on Evaluation of Volcanic Phenomena,Plant Site Remains Suitable
ML19331C892
Person / Time
Site: Trojan File:Portland General Electric icon.png
Issue date: 08/05/1980
From: Eisenhut D
Office of Nuclear Reactor Regulation
To: Mcmahon W
AFFILIATION NOT ASSIGNED
Shared Package
ML19331C893 List:
References
NUDOCS 8008200028
Download: ML19331C892 (32)
v • d • e


Text

{{#Wiki_filter:__ OEe LOCAL PDR g UNITED STATES y g NUCLEAR REGULATORY COMMISSION 7, E WASHINGTON, D. C. 20555 [ August 5, 1980 %.+ Docket No. 50-344 THIS DOCUMENT CONTAINS Mr. William B. McMahon 5625 North E Street POOR QUAUTY PAGES . Springfield, Oregon 97477

Dear Mr. McMahon:

~ This is in response to your letter of June 5,1980, regarding Mount St. Helens and the Trojan Nuclear Plant. In response tr your concerns, I am enclosing a technical report which discusses in detail the possible impact of volcanic activity at Mount St. Helens on the safety of Trojan. The report is in the form of an affidavit which was filed with the Atomic Safety and Licensing Board in the Trojan spent fuel pool proceeding. Although this report was filed prior to the recent volcanic activity, it is with few exceptions considered an accurate assessment today. Exceptions to the report include (1) the underestimation of the volume of debris associated with a potential mudflow, (2) exclusion of a discussion of volcano-induced earthquakes, and (3) the statement that historic data indi-cates that the volcano has been.substantially more active in the 19th century than the 20th century. Notwithstanding the above exceptions, the report's conclusion that the Trojan site is suitable from a volcanic hazards point of view remains accurate. 1he recent massive eruption of May 18, 1980 exceeded that envisioned by the Nuclear Regulatory Comission and by our advisors, the U. S. Geological Survey. Nevertheless, the effects of the recent volcanism (mudflows, earthquakes and ashfall) at the Trojan site have been minimal. Mudflows in the Toutle, Kalama, and Lewis River valleys have not compromised the safety of the Trojan plant. Volcanic-induced earthquakes have been small and have neither been felt nor recorded instrumentally at the site. Ashfall at the Trojan plant resulting from the May 25, 1980 eruption has been slight (not exceeding 1/8 of an inch) and fell at the site in the form of a muddy rain or mist. The only other indication of ash occurred on April 29, 1980 when a thin coating of the ash was noted at the Trojan site. According to University of Washington seismologists, the volcanic-induced earthquakes mentioned previously have not exceeded Richter Magnitude 5.1 and have been concentrated in an area roughly coincidental with the volcano crater which is 35 miles northeast of the Trojan plant. None of the larger events (Magnitude 5.0 and above) have occurred closer than 35 miles to the plant. For the most part, the volcanic earthquakes have occurred at shallow depths and have consequently been felt only in the immediate vicinity of the seismic event. However, there have been unconfirmed reports of volcanic-related earth-quakes (originating at Mount St. Helens) being felt in the Longview-Kelso, Washington area, roughly five miles north of the Trojan plant. Apparently, those feeling the tremors were located in areas where soil overlies bedrock. 8008200 6 3 k

m Mr. William B. McMahon The plant is designed to safely withstand seismic levels of 0.259 peak ground acceleration. This corresponds to earthquake levels many times greater than those generated by the volcano-induced earthquakes. The potential impact of volcanic activity on the safety of the Trojan facility ' was investigated thoroughly by government geologists (Atomic Energy Comission and the U. S. Geological Survey) before the plant was allowed to be constructed where it is. This investigation and reassessment of volcanic-related hazards has continued as attested by the enclosed affidavit. We have been in constant contact with numerous state, governmental agency, and university scientists since initiation of earthquake activity and subsequent volcanic activity in the vicinity of Mount St. Helens on March 20, 1980. This surveillance and accumulation of information will continue as long as the volcano remains active. Our conclusion, based upon an evaluatior, of volcanic phenomena prior to con-struction, coupled with an assessment of the effects of the activity beginning March 20, 1980, is that the Trojan site remains suitable from a volcanic hazards viewpoint. Nevertheless, we will continue to monitor, accumulate, and assess information related to the renewed activity at Mount St. Helens as it might apply to the safety of the Trojan Nuclear Plant. In response to your request for information on nuclear power, I have enclosed a copy of the NRC 1979 Annual Report. Sincerely, d JL [t' Darrell G. Eisenhut, Director / Division of Licensing Office of Nuclear Reactor Regulation

Enclosure:

1. Affidavit of R. B. McMullen 2. 1979 Annual Report cc w/ enclosure 1: See next page

cc: Mr. J. W. Durham, Esquire Donald N. Godard, Supervisor Vice President and Corporate Counsel Siting and Regulation Portland General Electric Cocpany Oregon Department of Energy 121 S.W. Salmon Street Labor and Industries Building Portland, Oregon 97204 Room 111 -Salem, Oregon 97310 Columbia County Courthouse Law Library, Circuit Court Room St. Helens, Oregon 97501 Michael Malmros, Resident Inspector U. S. Nuclear Regalatory Comission Trojan Nuclear Plant P. O. Box 0 Rainier, Oregon.97048 Robert M. Hunt, Chairman Board of County Conraissioners Columbia County St. Helen's, Oregon 97051 Director, Technical Assessment Divisio Office of Radiation Programs (AW-459) U. S. Environmental Protection Agency Crystal Mall #2 Arlington, Virginia 20460 l U. S. Environmental Protection Agency L Region X Office l ATTN: EIS COORDINATOR 1200 6th Ave..a a ~ Seattle, Washington 98101 i

g, Utijstu diAin U. n..m.4 tiU LEAR REGULATORY CO?c4ISSI0tl BEFORE THE ATO:4IC SAFETY A.10 LICE!;SI?!G SOARD In the l'atter of PORTLA!iD GENERAL ELECTRIC COMPAfD', ) Decket tio. 50-344 ET AL ) (Proposed Amendment to Facility ) Operating License tiPF-1 to Permit (Trejan I'uclear Plant) ) Storage Pool Vodification) ~ AFFIDAVIT OF RICHARD B. MciULLEN STATE OF MARYLAND ) SS .c COUtiTY OF M0tlTG0MERY ) l T' u I, Rich'ard B. PcMullen, being duly sworn, depose and state: 1. I am a Geologist in the Geosciences Branch of the Office of t uclear Reactor Regulation, U.S. !!uclear Regulatory Comiission, 'lashington, D.C. 205S5. 2.- I have prepared the statement of Professional Qualifications-attached hereto, a' d, if called u,pon, would testify as set forth therein. n t 3. I have prepared the a'ssesscents on landslides and volcanism attached hereto in response to the Atcaic Safety and Licensi'.g Board's Order of January 9,1978 and I bereby certify that the statements made herein are true and correct tc the best of my kr.awledge. AD8 MYS 9 9 Richard B. VcMullen. Subscribed & sowrn to l hefere me this R* day of A;ril, 1978 l O-., S d T;.L3

  • i

?i::?.ryFuolg i My C:. mission expires: O A - ), R'1% 9 \\ l l

60 a. m..a.t, O 3: e.. W i. N.e .% a b I.'? M.7*f.C C T. C 6 e f. r f.. g ?

      • r 3 *..* ^v.* 3 g...

2.. u C.r*.C4.* *. g n.*

  • r3 e p.

9.*.3 ey e r v,.t.y e ?.J s.f .g. a.;14= 4.,. e a s o n., g = at. .m f..... W;3 =. g e =...,. e.g.e. v.4 b. . 6..%.. t.. .J w. ., 6 e... c... e.* ..e.. .U Ae4A.y ov.. 3. w .1 .A s. s.. .ta.ct ry ....s.s. c *s. .%..e oc 5 t...es .....L., r ge. s...: 5. s.: - s..s A .y.s.C t....t.e,. 9..,y S. 4,.e.... ?. 2a.

  • e.. t..a...y

,a oSgs.. wy... t.g e.. .... w r. ..... -. u,: e. (.? ) .t.. e e. v.. a. s.... c.s e.se.e.9 s.,a. t s* .J... s.,. s.. h.sS.,cs.s. s s as;e::s =f s'res fer :.-c1 Car ;cver genera:1:g facilities; (2) a:aly:ing

s... c... e t s.g.g. c.-. i... 2 da.a < '.. *,. e ' * - _'. e V. s.'. s.,,c -.

1 .A .r. .,.e.a.s .e....,ea. e ss.a.:ts. . e .,.,lsC ts. s fc ... S.rt..s.,. .a-. r a-.s..-. s..-. s ?.......- '.e ae- 'a...y ( ' ) .2 v e 1 ~..,."....-. s.. -. ' a..... J. s s s.. < < c C... s. e e, s. g a...e.. s.... s. - _a..e.s. A s. e. ...r. e. 4 c.

s.....

.... g e,, e. s.. .u. v.s. e .. s. a.. e. J. e.J.u.e. r e.S..,.:..r... e.. a s., s e .r s.. rr t.* .y. -...s. . a. L... t.J s. c. 9 ..e.. g a 3..e. .Jts..t.. g..2 J. .. - s 3., ... s. r.. .s s. ..eSr.._;e...e .....ses s.2,3 s. s ss.s-.. 1 c..t,.. ,<.e.e.J s .r.,-.... cegineer'eg nd qu rryirs s;c.scred by the A: y Ingineer 50' :ci a* 5.~.,. ,-.. Ses. .st t *.* t..S C.s g... - J.s..s..S .2 s s 1 .r. 24.N..f,., a+4.,

    • C -. E s S.

1 a..a s..t~r.t.s E=

  • 2 3.t sh S.t t=J C

S. ...u..s, 27.* s.r- = ~ ......s ba.s.t_ s...~a. %v..s .C.s.g Os.s. s. s. 18.z.a.E ,, e .) .s n. . -"... e g. *g*a *. r 5 * .b a..- A.r.C. ...,s.....s-k,..'4 C.J US A .s.o t.i J .t.?..eS. g.s.s t 5 .*.6-b '.-.<...- .. g.c. t.c. 3..a.1 .c. t. J. s

?

..a. ..e. ,tfg .e e. < - e. a.s. -...J....: --...-6 S -b ,1 J a -.S. s..' s + a y s.5.a1*.a.s s,.a.a. .. m...J C o... T ?. s.........ts, .?

665,

(*

  • ....*b...'..-

.'tXSS. E*.*a ' ". a *. t.'. a ' *..-*. *. t *t*c'.*3 ~ S '. *. C 5, *** ' '. 5 5 ' '..a a. b s* . r ~. . J.. ....s s o s.. tO*... S..-..~.e 4. "Aet --~~.**.*~go e...c.'i..$.}.e S....s ...%ye b .....g. 5.- .-e . a 4..?.s.:. 45 4 P...sJ...a. t .. J

6..t. J.,.. s.

C.. s. . C. 4... , e..S t... J a -..s.SE ...--6 .r .s. e. ES....As.e5 *S.1&.>,, a,-.J 1 e .s.., .a s..,. S l a... S. ...t... Se..t.a.. A.w. .c :.< 24 5 Pa a 4.a1 . 6 3 *.... S J.. .s. E C..-r5 1: 5.r.. f. i .1.. .3 -5.- 4 ... w. v.$..s. . C(fs.. C.,,., e .%.. tt..., ;*..s >a,.ss S. a5 a S.a..t 2:s.s t t.s.. g s 94 J. .s. 5 >.eS.

c. ut t...

5 .y.J... : tS V S.t 1.a., w .4 9.s. v %3.sS., 3 . r .c.. J..a.s.. .. S 2.s t3 .c .a*. ., 2 T. .Jt..... t.t t %., s... C .s. 3 n,. u.. S s....s.. K J ...S_z.s.e .1 y. J. S.... 2

g..e.. & e.., J.

. 2. s.'. s.. : 2 5.r...s. t $_sy s.=.3 - g. r..s a .s E.xa. a.t.J 45 .b..E As 7...t. a..2. v

  • ....r

? ..*.s w.. ...n .3 ,., g,.,.. e 5 a.> a..ss..E.-..a1 g..s et.*S.' - .. A.. g g., t.y... ~6-C.... C $ o.r S...... a. c. J... & a. S, Oc.s...g. . s. t t J .J.,,,. t.

s... f t S s..,

.r r... g.. a..t.. ...S..,..s. , a. J. .t. 4.J. t.J s. c.. J..s. S A.... s. $ a.. J. .r. ...C s .C.. 4.... r... . g. 2.. g3 g.s. gg y.es..g. .A ..J,c.u...t. . ts. t s s a. y .r e..~sa.s.C. ..,g t. j y. .... n. s .C'3... a-.J g.~., a..s.-. gg ..g

f. *.... s

.....s.,, 5g. ,3 .s. .....3 ~ .w. .o .. e 3....e, .t.*..y, s ..s.. Jts.s,

s. 2-s

.. 5. .. s.. . - s... S Ct . *. t s.....S. s. 3 a...- a .r s w. a....a e.a..t.o C.s..CSC...,. S. r.. .a.. : C.,,3.z. g ,... s .s . ES E s.y. g., t,,..u5 a.J s.. '.c. L. s J

  • c. c... =. S. C..

e --e-r a.. .s..c.A.t .s. .? .s. .S.s ... S .c....,.. S,.;. S ea *.t..t.3 , 1.t.... 43 r.. .e ...t.t3 S.. ~....SS.s ...S.S.E.J J --- s .%..e s....,S. ,,4 4. c.... ...s. .~r S..,.a. J....st.t s.

r. au.. g. S t.: :.

t...a. y T. 2 ...J ..A. ..s J. c.....J. s,2 s...syS. 1.t rr..s ...r-4 . s. s... S S..,.g. g... t .s s.C*J 6 ? _.s e...g g en.,*.y,A.

4..,..

5 y. a r.,. ..g. L.:, t-s, s.. J T. .=.-s-. n .S--- ...S s.. ..S. S..t...., .. c... t. e r--..... % y . *a s .~ -..--e h-m. m m.

  • b tr:nsferred to the H:ntsville, Alsbcn: Corps of Ensincers Division which was responsible for the siting, desisn and censtructica of 15 to 20 (later reduted to 4) safeguard antibalistic =issile installations thrcushout the United States. ::y dutics there were to plan, direer and participate in investigations to determine the suitability of these sites for c nstruction of the eissile cenplexes.

I perfer=ed geolegical studies and soaa soil =echanics verk to develop design parsncters for feundations and excavstions. I also served as technical censultant during design and construction to other governnent agencies. architectural engineers, nd contractors. I have been a eerber of the Regulatory staf f since January 1971 and have participated in licensing activities for at least twenty-five nuclear facilities including Su==ar, Nine-> ile Point, 'a'a shing ton Nucles: 2, Febble Springs, anc Indian Point. These activities con- .sisted of review of the geolegical aspects of the sites as presented by applicants and usually an independent evaluation conducted by a review of the =ost pertinent literature, site visits, and conversations 2 with kncvledgeable individuals or agencies. i t i 4 i b a

A. Landslides- - - \\ 1.

  • RC Posit f ens Af ter LP.ind OL Revir s j

In its.Cafety Evsluation Report (ST.R) for the Trojan site dated Ccte-Ler 19,1970, the staff concluded that *3ased en the evidence pr:vided by the applicant cad field observations of cur geclogists and our geologiral ccitsultants, vc have concluded tha: the existing geolcgical structure is acceptable for the constructica and cperatica of the pinposed plant at the Trojan site." The U. S. Geological Snevey conclud.d that, the applicant prep:ses to fcund all =ajcr plan: structures in the volcanic rocks. 3oring icgs and test data indicate that the reeks are sound and vill provide an adequa:e foundatica for the prcpesed facility." In its SER fc11cving the CL review, the staff reaffirred its criginal cenclusiens. 2. .Cu.rrent Staff Fositiens It is the s:aff's position that lar.dsliding in the site area does not present a threat to the Trojan plant. This conclusion is based en our review of several recent publicatiens en landsliding in the regien and the results of geological investiga:icas in the site area including horings, scisnic profiling, surface geologic =spping sad the geophysical i=vesti-cations that were supervised and evalunted by the Trejan Geophysical Mvisery Peard cospris. d of Dr. Petersen, Dr. L'ai:e end Mr. Dodd. The resul:s of :hese studies indicate tha: the i = ediate site area does not have the characteristics which typify large landslides alcng the Columbia River. e .-y ,-,-r-w w ..y w-y

2 3. b@inv.in.1 r......rectiv iir f..ir m. I:niel.t I.h s in the f:olumbia River Corce Palmer (1977) studied several large lendslides that have occurred within the Columbia River Corgo. These slides were in an area characterized by steep terrain with relief on the orcer of 1200 'acters, high rainfall (::30 en/yr.), exposure of water saturated plastic cisy laycrs under permeable rock masses, and regional dips of rock strata from 5 to 30' into the gorge. A thick stratigraphic section of the Eocene to Oligocene Chanapecosh formation underlies the area studied by Palmer. This formation is made up of varied claystone to pebble conglomerate of both sedimentary and volcanic materials. Portions of this rock hs.ve been weakened by weathering. An angular unconformi.ty in the Miocene caused the develop-ment of a zone of soft clay rich saprolite on top of the Shanapecosh formation. The Miocene Eagle Creek formation overlies the Chanapecosh. The Eagle Creek is similar in composition to the Ohanapacosh'but is less weathered an.d contains larger rock fragments. On the k'ashington side of the river, the strata within these formations dip toward the Columbia Gorge, while on the Oregon side they dip away from it. Basalt overlies the Eagle Creek formation. River banks were overstecponed as the Columbia River cut through the basalt into the weak Eagic Creek and Chanapocosh formations. Most large l scale Pleistocene and lioloceno landsliding occurred on the !.'ashington shore vhern overstecpened' slopes intersected the bedding i i pl.,nes of exbosed inconpetent rock, which dip to the south into the gorge.

i. esser slides are found on the Oregon shore where several thousand feet of l

l 1 ,.e

3 basalt overlic the cl.sy of the Engic Creek and chanapecosh formation which dip away from the gorge. The combination of exposure by croslun of the clays and the weight of the basalt caused squeezing updip of the clays, eventually undermining the basatt and cauding large rock falls.(Palmer.1977). 4 Geology and Topography of the Site Bedrock bcncath tne Trojan site consists of volcanic rocks of the Upper Eocenc Coble series. Boring, seismic, and laboratory test data show that the rock is relatively sound and composed of tuff, flow breccia, tuf f breccia, agglomerate, and basalt. Bedding planes within the rock are poorly developed, but those that have been mapped generally dip toward the west-southwest or southwest, away from the Columbia River. Coophysical data indicate that the volcanic rock also underlies the Colunbia River cast of the site thus precluding the exposure to crosion of continuous clay strata like those described in the Columbia River Corge (Palmer,1977). The topography along the river valleys in the site region is characterized by many steep arcuate features. The Trojan site is located on a bedrock ridge just east of one of these steep arcuate features within the Columbia River Valley. This valley was subjected to intense flooding o during post glacial time (Bretz 1969). It is likely, based on geologic evidence at the site, that the arcuate feature is the result of river. bailk scouring and erosion from rapid flood stage flow through a since-e

4 abandoned channel of the Cnlu-bia ?.1 var, rather than landsliding. Similar abandoned channels were repor:ed by Piteau (,1977) following his study of landslides in the Fraser Eiver Valley in southern British Col ue.h i a. Piteau also presented evidence to show that the major single enuse of landslides in that area was the presence of alluvial fans or carlier landslide debris on taa opposite side of the river, which i deficceed the river laterally and caused undercutting and oversteepening of slopes. Such,.ocesses are not active at the site. 5. Bases for Staff Position Although landslides are evident in the site region, landsliding is not likely to pose a hazard to the Trojan site. The staff concludes that the Trojan site is not susceptible to landsliding for the following reasons: 1. Available data indicate that the velcanic bedrock in the site area is continuous from the hi'Is vest of the site, bonesth the t alluvial valley, through the site ridre, beneath the Columbia River, and on to the h*ashington side, and is not an active slide block. 2. Interpretive seisnt: profil.es sh=v that the surface of the bedrock bencath the alluviated channel is s=cothly rounded, as vould be expected in a rapidly eroded bedreck channel, and not sharp and angular as would characterize a relatiro*.y recent and unstable slide block. O l 9 S w -r--n.-, ,n

.e 5 3. Rock strats beneath the site and the area arcund the site on the Oregon shore dip, with relative consistency, southwest or west-southwest away from the River; and data presented by the applicant indicate that joints and shear zones are either not continuous or dip at steep angles, thus precluding the existence of a potential slide plane sloping toward the river. Geologic maps of the site vicinity o'n both sides of the Columbia a. River show that bedding dips either 'in a southerly or westerly ~ direction. b. Figure 2.5-16 in the FSAR, which is the Geologic Map of Final Foundations, shows that joints and shear zones are either dis-continuous, dip away from the river, or dip at a high angle such that a projection of that dip would not intersect the river valley. Correlation of bedding from boring to boring and interpretation c. of geophysical data show that, locally, bedding planes below founda:_ level are generally horizontal or dip away from the river. d. On a broader scale, based on geophysical data and surface .aapping, the site lies on the eastern flank of a northwest trending syncline within which the bedding dips to the west, away from the river. Dips of strata beneath the site show no evidence of rotation of e. beds as would be expected within a landslide mass.

.. f. The USGS revicver exa:Ined the excavation for the plant on 1 October,1970, and reported that alth'ough no real bedding plancs were visible, some nearly horizontal, crude separations were observed that were consistent with observations made in natural cxposures' of these rocks nearby. 4 Based on a projection from mapped outcrops, the volcanic rocks underneath the site rest on the Cowlitz formation, which is described by the Applicant as well compacted but sometimes loosely cemented sandstones and siltstones. Sandstones er siltstones are generally less suceptible'to landslide development than clays, such as those described (Palmer 1977) as being part of the Eagle Creek and Chana;ecosh formations. It is possible that there are clay zones in the Cowlitz formation beneath the site, either from deposition or weathering. However, the Cowlitz for=ation was subjected to the same deformation as the overlying volcanics, and bedding planes would likely dip in a westerly direction, away from the Columbia River Valley in contrast to the bedding in other parts of the gorge where large landslides have occurred. 5. Aeromagnetic and gravity profies show no anomalous break that might be associated with bedrock sliding. 6. A major landslide upstream could temporarily block the Columbia River; hor:ever, the site intake facility is located at a sufficiently low elevation relative to sea level, that'the source of emergency cooling water v.culd not be cut off.

= t 7 7. In its report entitled " Geologic Hazards Review Trojan !Nclear Power Plant Site Columbia County, Oregon," the Oregon State - Department of Geology and i4fneral Industries concluded that "available geophysical data and geologic information collectively 4 indicate that the site area is underlain by continuous bedrock and that deep mass movement is not a factor". J i It is therefore our conclusion that landslides do not pose a potential threat to the site including the Spent. Fuel Fool Facility. g g e I b i J 4 4 ) 1 i ~ l 1 o 6 11 I e m -2,-,,,% -,,-.-sv+sw,-,- ,,er.---.-w---,+,-,m ,,wp,--ve,.,-,-,.-w,,,---w-,g..-,-m-,v.wy,og-.,_.-r.y,, -,,,=,, .,,9my ..-e,y-p. ,wq,-,.9, e.,,-g+, m-

O t References for Part A. Landslides 1 1. Uretz, J. H., l';59, The Lake Missoula #1;cds and the Channeled i Scabland: Jour. Geology, V. 77, No. 5, p. 505-543. I 2. Palmer, L.,19/7, large Lar.dslides of the Columbia River Gorge, Oregon and Nasnington, Geological Society of America, Reviews in Engineering Geology, Volume III, pp. 69-83. 3. Peterson, R. A., J. E. White & R. K. Ocdds,1972, Geophysical Survey Report Trojan Nuclear Power Plant Site; Prepared by the Trojan Geophysical Advisory Board for the U. S. Atomic Energy Commission, August, 1972. 4 Piteau, D. R., 1977 Regicnal Slope - stability Controls and Engineering Geology of the Frazer Canycn, British Columbia; Geological Society of America Reviet.s in Engineering Geology, Volume III 1977. 5. Portland General Electric Company,1973, Final Safety Analysis Report Volume 1. t 6. Portland General Electric Company,1969, Preliminary Saf ety Analysis Report, Trojan "uclear Plant, Volume 1. 7. State of Oregen Department of Geology and Mineral Industries, 1978, Geologic Hazards Review Trojan "uclear Pcv.er Plant Site Colu:ibia County, Oregon, Open File Report 78-1, March 14,1978. 8. U. 5. Atomic Enercy Commission,197', Safety Evaluation Report Trojan Nuclear Plant, Docket No. 50-344, October 7,1974. 9. U. S. Atomic Energy Ccmmission, 1970, Safety Evaluation Report by the Division of Reactor Licensing, US AEC, In the Matter of Portland General Electric Company, City of Eugene, Oregon, Pacific Power and Light Co., Trojan "uclear Plant, 00cket No. 50-344, October 19, 1970. 'l' 1

.o B. Volcanism 1. Staf f Position Af ter CP and OL Reviews and Current NRC Position In its Safety Evaluation Report dated October 14, 1970, following the Construction Permit review, the staf f concluded that: "The applicant has evaluated potential lava flows, mud flows, and volcanic ash falls and determined that they would not adversely affect the safe operation of the Trojan reactor. We and our consultant,s, USGS, have reviewed the applicant's evaluations. We conclude that the assumptions and evaluation techniques used by the applicant were reasonable and we agree i with the applicant's conclusion. In the Safety Evaluation Report (October 7,19 74), af ter reviewing the Final Safety Analysis Report, in support of the application for an operating license, the staff concluded that: " based on this review, we c'onclude that investigations conducted since the issuance of our Safety Evaluation Report dated October 19, 1970, have disclosed nothing that would alter our original conclusion regarding the suitability of the Trojan Plant Site." Since publication of the SER, new information has become available. We have reviewed these data and we see no reason to change our original conclusion. 2. Basis for the Staf f's Conclusions Following the CP and OL Review During the review for the Trojan site the following potential volcanic hazards were evaluated as to their significance to the Trojan site: ashfall, mudflows, pyroclastic flow, flooding, and lava. Crandell and e 6 4

y,--w

Waldron (1969) indicate that if one of the Cascade volcanoes erupts, "we believe that ash eruptions and cudfie s are the two greatest hazards." a. Volcanic Ash. Ash is made up of fine volcanic particles that have been blown high into the air by explosions in a volcano. The extent and thick ~ ness of ash fallout is in'fluenced by the altitude to which it has been erupted, sizes of the particles, the directions and velocities of the winds, and other =eteorologic conditions. Mount St. Helens is the closest (.33 miles east northeast) and most likely source of ash that could affect the site. The applicant stated in the PSAR that even if the ash fall from the Crater Lake eruption were superi=pesed over Mount St. Helens, the resuiting ash fall would not have damaged the plant, nor caused interruption of the cooling water supply. Crater Lake is located in the Cascade Mountains in southern Oregon and was formed by violent eruptions of a volcano Ott. Maza :a) about 7003 years B.C. The staff agreed with that conclusion on the bases that : (1) the. site lies near the maxi =um extent of ashfall when the contours showing the distribution of ash from the Mt. Mazama eruptions according to Williams (1942) are superi:. posed en Y_ cunt St. Helens and other nearby volcanoes (PSAR Figure 2.8-16) ; (2) the prevailing winds blew away from the plant teward the volcano rest of the time and apparently hcve done so for thousands of years; and (3) the source of crergency cooling water is the Colc.bia River. m 9 ..,,,-,,.g e.,r-.+ +,e-y,w,.e., ir. vr-,- =,+--y.-- -,-.,-,r-w%.i,,,-r..- w

b. Mud flows. "Mudficws are masses of water saturated rock debris t which cove downslope in a r.anner resembling the flowage of wet concr e te." (Crandell, 1976). Mudflows have been known to move many tens of kilometers down valley floors at speeds of 35 km/hr or more (Crandell,1976). ne possibility of a mudflow from Mount St. Helens endangering the site was considered during the CP stage. The applicant concluded that, "A large mudflow on Mount St. Helens vould likely move either down the Kalama River Valley or the Lewis River Valley. The couth of the Kalama River is close to the Trojan site, but on the opposite side of the Columbia River. It does not seem credible that a debris flow down the Kalama vould even reach i f the Columbia River, let alone that it could block it. If it l l reached the Columbia River, its probable worst effect would be to l muddy the river downstream as the Columbia removed and diluted the I flow of debris e=ptying into it. The slopes are so flat at the point where the Kalama discharges into the Columbia that a mudflow extending that far would be moving very slowly." The staff also concluded that mudflows did not constitute a hazard to the plant. c. Floods. Floods can be caused by melting of snow on the flanks l of a volcano. These floodwaters can carry large amounts of rock debris which can be deposited many kilometers from the volcano. An analysis of the flooding potential due to volcano eruption was I l I l l t

s - t, - 4 nade by PGI during the CP stage of the licensing process. The vorst case situation was failure of dans and reservoirs along the Lewis River. It was concluded that flooding from the Lewis River reservoirs would not raise the Columbia River enough to inundate the plant. A similar analysis was not done by the staff; however, the staff's hydrological engineering analysis showed that the plant was safe from flooding even assuming the failure of upstream dams including Grand Coulee Dam. Any flooding caused by volcanic activity would be less severe than the failure of upstream dams on the Columbia River. d. Pyroclastic flow. As defined by Crandell (1976), pyroclast'ic flow is a cass ef hot, dry r'ock debris that coves rapidly down the flanks of volcances. Because of the distance that Trojan lies from the nearest velcano, and the t spography, pyroclastic flow was not regarded as a hazard to the site. e. Lava Flows. According to Crandell (1976) lava flows generally erupt quitely, but can be proceeded by explosive activity. Lava flows are usually cenfined to the immediate sicpes and toe of the volcano. In order for lava to reach the site it cust be highly fluid and of 3reat volu e. This is not characteristic of Mount St. Helens and there is no evidence that lava fres this volcano reached the O-G l ~, -

-5 Columbia River. For these reasons lava flows were considered not to present a hazard to the Trojan site. 3. Variation of volcanic Activity in the Pacific Northuest De staff finds no evidence indicating that there has been a recent increase in activity of Cascade volcanoes. Evidence is that future activity will continue nuch as it has in the past 10,000 years. De volcanoes nearest to the Trojan site: Mt. St. Helens, Mt. Rainier, I and Mt. Hood are considered active volcanoes. H e available evidence indicates that activity has been essentially constant though episodic for at least the last 10,000 years. Historic data show that Mount St. Helens was substantially more active during the 19th Century than during the 20th Century. The enclosed figure is a compilation of known activity of several ' Cascade volcanoes including those most significant to the Trojan site. ne illustration is base'd on data published by several' investigators.,which was presented in Portland General Electric's report entitled " Volcanic Hazard Study, Fotential for Volcanic Ash Fall, Pebble Springs Nuclear Site, Gilliam County, Oregon." It can be seen from this illustration that Mt. Rainier and Mt. Hood have undergene sporadic activity for at least the last 10,000 years and Mount St. Helens for 4,000 years. This type of activity is expected to continue in L'ne future. k'orldwide data on plate tectonic activity support this interpretation. The volcanic activity is related to processes at the plate boundary in e Y s

. this region. Data indicate that plate tectenic activity in the United States Pacific !!orthwest is either continuing at a relatively slow rate as co: pared to sest tectonically active regions around the world, or has stopped co:pletely. This would explain the relative inactivity of the Cascade volcances, when coepared to world wide data. For exa=ple, in the vicinity of the Aleutian Trench, where the Pacific Plate is actively subducting beneath the Alaskan Plate, volcanoes have erupted far core frequently historically and with greater violence than in the S. Pacific :*orthwest. It is not possible to absolutely rule out that Mt. Hood, Mt. Rainier, or :t. St. Helens could experience similar eruptions like those that . forced Crater Lake. Crater Lake was created af ter violent eruptions of ::t. ::a:ana about 7000 years B.C. Houever, such an occurrence is considered to be very unlikely within the next few centuries (Crandell and :ullineaux, 1975). It would represent a complete change in activity from that deconstrated' during the last 10,000 years for Mt. Hood and i Mt. Rainier and 4000 years for Sunt St. Helens. Such an eruption at one of these volcanoes occurring si=ultaneously with the wind blowing tcward the site is extremely renote. Therefore it is reasonable to assra that the "orst events that have occurred in the geologic past at a specific volcano could occur there again. i i e e i

7-It is_ the staff's position that any increase in volcanic activity that is postulated, based on a study of the activity of the Cascade volcanoes for the past 10,000 years is not likely to present a hazard to the Trojan site. We believe that there will be no increase in activity based on the experience of the past 10,000 years. Evidence from the plate tectonic theory supports this position. 4. Data Subsecuent to the SER's Considerable additional studies have been ma& of t rolcanic 5 hazards of the Pacific Northwest since publication of t.te Safety Evaluation Reports. Many of these studies have been conducted it. regard to the siting of nuclear power plants, such as the Washington Public Power Supply System (WFPSS) Nuclear Project 3. and 5, the Puget Power Skagit site; and the Fortland General Electric Pebble Springs site. The data included in the reports supporting license applications for these sites are compilations of data from many investigators. The USGS has published studies of volcanoes in the Pacific Northwest, among whP.t are volcanic hazard assessment caps (Crandell,1976 and Mullic. aux, 1976). The analysis of volcanic hazard for the WPPSS 3 and 5 site, which is 80 miles from the nearest volcano (Mt. Rainier and Mount St. Helens) indicated that only ash could affect the site. It farther showed that less than 2 inches of ash would fall at the site even if the assumption is made that a Mt. Maza=a type eruption occurred at Mt. Rainier or Mount St. Helens. 4

-S-I Based en a recce::endation fres :he USGS, Puget Fever postulated that a nudflow sinilar ta the Osceola tudfiev frem Mt. Rainier could occur at Mt. Baker, which is about 22 niles east of the Skagit site. The analysis showed that such a mudflev vould not adversely affect the site. Ashfall is believed to be the only form of eruption that poses a direct hazard to the Skagit site (USGS,1977). The Skagit site is located about 56 =iles from Glacier ?cak, the nearest volcano with an explosive history. Based on the superposition,of the 1912 Kat=ai Alaska eruption on Glacier Peak, about 2 inches of ash would fall at i the site. The Applicant assumed a maxi ts ash accumulation of 6". I The staff and the USGS concluded that this was a conservative approach. Unlike the WPPSS 3 and 5, Skagit and Trojan sites, the Pebble Springs site is located east and downvind of the Cascade volca$oes. During the review of the volcanic ha:ard for the Pebble Springs site, it was our position, and that of the U. S. Geological Survey, that a i conservative and reasonable estimate of a raxi=um potential ash fall i at the site shculd be redeled after the Yn ash layer which vas erupted - i fres Mt. St. Helens between 3,000 and I.,000 B.C. This analysis resulted 4 i in the cssumption of a thickness of S 1/2 inches of unce=pacted ash at the site, which is located S0 miles and 105 miles east of Mt. Hood i and Mount St. Helens respectively. Since publicatien of the SER's the 4 USGS has published 2 Volcanic Hazards Maps (Crandell,1976 and Mullineaux, j 1977). ~he former designates :enes in the state of Washington within 3 I 4 i I _m.,._.,,,_y_,.,.. _. _.,,, _ _. -,. _., _ -.,,. ,_y,,.. ,,,,.c .,_m...m..,

. which specific volcanic hazards are possible. The latter shows volcanic hazard zones in the western United States. The USGS also open filed a report entitled Potential Hazards from Future Eruptions of Mount St. Helens Volcano, Washington (Crandell and Mullineaux,1976). 5. I:maet of Subsequent Data on Original Conclusions Based on the data that the staff is aware of, which has come to light since the CP & OL proceedings, the only form of volcanic eruption thct could directly affect the Trcjan site is ash fall. 'However, new information has become available regarding several of the other potential hazards. These will be addressed first, followed by a discussion of ashfall. Crandell (1976) and Figure 2.5.18 of the WPPSS Nuclear Project No. 3 Preliminary Safety Analysis Report, which is based on data presented by Crandell (1973), shows mud flow deposits just north of Longview, Washington in the Cowlitz River Valley. During its evaluation of this phenomenon PGE concluded that because of thi distance from the ~ volcano, and consideration that the intersection of the Cowlitz and Columbia Rivers was located downstream from the plant there was no potential hazard to the Trojan plant. Crandell (1976) also shows a potential mudflow hazard within the' Kalama River Valley extending to about 8 niles from its intersection with the Columbia River. This does not present a threat to the Trojan site. Much larger mudflows have occurred in the region such as the Osceola mudflow from Mt. Rainier, e a .-- 4 1

which t s used a.s a rodel for the caxiet= possible nudflow during the Ska;;it site retiew. Howaver, since Mount St. Helens is a relatively yotog and unal:ered volcano, one would not expect se:h large quantities of potential cudflev material to be available on its flanks as on those of the o*_ der altered volcanoes like Mt. Rainier and Mt. Baker. According to Cra= dell and Mullineaux (1976), "The absence of an appreciable ar.:unt of clay in mudflows from Mount St. Helehs suggests that large areas of hydrothermally altered rock did not exist on the volcano in the past; nor are they present today. For this reason, tudflows as large as the largest from Mount Rainier volcano (Crandell, 1971) are not ~_icely to occur in the foreseeable future at Mount St. Helens." Beca:se of the distance from the Trojan site to the volcano, the nature of the intervening topography, the site being outside of the tudflow ha:ard zone specified by Crandell (1976), and the youthfulness of Mount St. Helens, we consider our earlier conclusion that mudflows do not constitute a threat to the Trojan site, as being still valid. Crandell C.9 6) shows the potential for volcano induced floeding at the Kalata and Lewis Rivers. As stated earlier, flooding from these sources would le less than the assu=ption cf failure of upstream dams on the Colt =hia 7.iver. The site is considered to be safe from such events. e n ~ ---- y. ...~, - -, -,--.-,- - -, - - w. -

4. We distributica and thic* cess _ of ash deposits east of the Casc:Ge 1 volcances are relatively well deeveented, at least these that crigina:ed within the last 10,000 years. The distributien of ash to the vest of the volcanoes is not well docunented, partly because the prevailing vinds blow mostly tcvard the east, therefore, nos: ash has been trans-ported in that direction; and partly because investigations have not been conducted vest of the volcanoes to the extent that they have to the east. According to Crandell Q976) "!ic significant a cune of tephra has fallen in the vestern sector beyond the base of t!.e source l volcano during the last 4,000 years at !!t. St. Helens, or during the last 10,000 years at the other large volcanoes in "Jashington." Crandell G976) and Ifullineaux (1976) selected the respettive tephra hazard

ones vest of each volcano to be 25% as great as those in the eastern sector, althrugh the few ash beds kne a to exist vest of their source l

vents are less dan 10% of the distance that similar beds extend east of the source vents Ciullineaux 19 76). This nu-Ser is not cenpietely arbitrary as it is based on the kncviedge that not only do the prevailing vinds blev to the east est of the ti=e, but en the rare occasicas when they are bleving to the vest, velocities are significantly less. This is denenstrated by at;;4ched tables 3 and 4 fren Crandell and !!ullineaux 1 (1976). i The Trojan site is near the outer beundary designated as zcne 3 by j IIullineaux G976), and described as an area subject to 5 c=s or =cre l 1

, of ash from a "large" eruption similar to the '. aunt St. Helens eruption about 3,400 years ago. The site is located in an area designated by Crandell (1976) as one of very low to lev potential hazard to kncvn human life and health, and one of probable taximum tephra thickness of less than 5 c=s. With regard to the spent fuel building, the weight of 5 cm of uncompacted ash on the fuel building roof would i= pose loads well within the design limits of the roof. (FSAR Table 3.8-2 gives live load design limits for facility roofs.) The staff concludes that infor=ation that has become available since publication of the SER's does not cause us to alter our original conclusions that the site is suitable froc a volcanic hazards stand-point including the spent fuel pool. 6. Conclusions a. It is the staf f's position that there is no present increase in volcanic activity in the Cascade volcanoes. Available evidence indicates that acti.vity has been relatively consistent over the past 10,000 years. The historic record shows that Mount St. Helens was far more active during the 19th Century than during the 20th Century. Future activity is expected to be similar to that which has occurred during the past 10,000 years. A very large eruption, like the Crater Lake eruptions, of one of the larger Cascade i volcanoes cannot be completely ruled out. However, such an ^ occurrence sinultaneous with high altitude winds blowing toward G e =e iw ww w-eme, - - - - - - - -.,, - - - + - - - y

the site is considered to be extremely remote. Any increase in volcanic activity that is postulated, based on the activity of the Cascade volcanoes for the past 10,000 years is not likely to present ) a hazard to the site. b. Because the Trojan site was shown to be safe from a more severe hydrologic event (failure of upstream dams on the Columbia River, including Grand Coulee Dam), floods caused by volcanic activity will not present a hazard to the site. I Due to the distance of the Trojan site from the Cascade volcanoes c. and the topography, pyroclastic and lava flows do not pose a threat to the site. d. Mount'St. Helens is a young, unaltered volcano; therefore, large quantities of potential mudflow material are not likely to be avail-able on its flanks. We conclude that mudflows are not likely to threate e site, e. Ashfall is considere represent the greatest potential 'azard in this part of the Northwest. It is ely that any ash will fall on the Trojan Plant because the prevailing winds v away from the plant and toward the volcano; and even during those rare ti.

  • when they blow toward the plant, velocities are significantly lower.

Superposition of the ash distribution from the Mt. Maza=a eruptions at Mount St. Helens would not adversely af fect the safe shutdown capability of the site. e 6 m e*

  • m emmuo mmee.

e-==, .m .e

===--.me.-m w w e- ----g e-- w+-y

o f. In its !! arch IS,1978 repc,rt to the State Depart.ent of Energr entitled " Geologic Ha:ards Review Trojan !;uclear Po.eer Plant Site, Colu=bia County, Oregon," the State of Oregon Department of Geology and }!ineral Industries concluded that "no new evidence has come to light to require modification of conclusions regarding volcanic hazards as they are presented in the FSAR." g. The Applicant committed in the SAR's to take the necessary steps to mitigate the effects,of a volcanic eruption including shutting down the plant. References in itees (a) through (e) to the " site" include the spent fuel pool. Eased on the above, the staff reaffirms its conclusion following the licensing reviews, that the Trojan site, including the spent fuel pool, is suitable from the volcanic hazards point of view. 4 l I I l l L

REFERENCES FOR PART B - VOLCANISM l. Ctandell, D.R".,1971, Postglacial lahars from Mount Rainier volcano, Washington U. S. Geological Survey Professional Paper 677, 75 pages. 2. Crandell, D. R.,1976, Preliminary Assessment of Potential Hazards from Future Volcanic Eruptions in Washington, U. S. Geological Survey Misc. Field Studies Map MF-774. 3. Crandell, D. R.,1973, ' Map Showing Potential Hazards from Future Erupt, ions of Mount Rainier, Washington, USGS lbp I-836. 4. Crandell,.D. R., and H. H. Waldron,1969, " Volcanic Hazards and the Cascade Range," Of fice of Emergency Preparedness, Region Seven, Geologic Hazards and Public Problems Conference Proceeding, Santa Rose, Calif. (May 27-28, 1969). 5. Crandell, D. R., and D. R. Mullineaux,1976, Potential Hazards from Future Eruptions of Mount St. Helens, Volcano, Washington, U. S. - Geological Survey Open File Report 76-491. 6. Mullineaux, D. R.,1976, Preliminary Map of Volcanic Hazards in the 48 conter=inous United States, MF-786. 7. Portland General Electric Company,1973, Final Safety Analysis Report, Volume 1. 8. Portland Cencral Electric Company,1969, Preliminary Safety Analysis Report, Trojan Nuclear Plant, Volume 1. 9. Puget Sound Power and Light Company,1973, Preliminary Safety Analysis Report Skagit Nuclear Power Project, Volume No. 4. i Shannor. & Wilson, Inc.,1976, Volcanic Hazard Study Potential for 10. Volcr:nic Ash Fall Pebble Springs Nuclear Plant Site, Gilliam County, Oregon, Revision 1,1by 17,19 76, Report to Portland Ccaeral Electric Company, l l 11. U. S. Atonic Energy Commission,19 70, Safety Evaluation Report by the Division of Reactor Licensing, US AEC, In the Matter of Portland General Electric Co., City of Eugene, Oregon. Pacific Power & Light Co. Trojan A*uclear Plant, Docket No. 50-344, October 19, 1970. I 12. U. S. Atomic Energy Commission, 1974, Safety Evaluation Report Trojan Nuclear Plant, Docket No. 50-344 October 7,1974 l A

13. U. S. Geolegical Survey,1977, Status of Reviev ?uget Sound Power and Light Company, Skagit Nuclear Power Project, Units 1 & 2 Project No. 514, Skagit County, *?ashington, ::F.C Docket Nos. 50-522 and 50-523. 14. State of Oregon Department of Geology and Mineral Industries,1978, " Geologic Hazards Review Trojan Nuclear Power Plant Site Columbia County, Oregon," Open File Report 78-1, :: arch 14,1978. 15. U. S. Nuclear Regulatory Commissio~,1973 Supple:ent No. 3 Safety n Evaluation Report related to construction of Pebble Springs Nuclear Plants Units 1 and 2 Docket No'. 50-514 and 50-516. s

16. Washington Public Power Supply Systen, 1974, Preliminary Safety Analysis Report WPPSS Nuclear Project No, 3 Volume 3.
17. Williams, H. A.,1942, "The Geology of Crater Lake National Park, Oregon," Carnegie Institution of Washington Publication 540, 1942.

t S 6 l __ ~- --

e i 2 9 9 4 4 6 5 W E N S 1 8 6 3 5 1 4 N S 2 2 3 5 4 2 3 9

~. E 6

3 7 . r 4 6 7 r. .~ W E o I S 2 9 5 1 6 3 4 p ' I 2 2 3 5 4 2 3

f. O f

. n I. B. t ii 8 2 8 4 3 i t e 1 1 7 t h W E l f s N S 1 9 7 0 6 5 5 a

n. v a oA W

E 2 2 3 5 4 2 3 . u /m ~J s y s u r r 5 0 4 9 2 7 2 o a e W E m t 3 1 8 6 0 6 7 /c /. ir m n 2 3 3 5 5 2 3 r

v. i a u e v S C

y 2 3 4 3 8 5 1 /n /. t t c W E af i S N 4 1 8 5 0 5 7 c. i t W E 2 3 3 5 5 2 3 / C .~l a )A m /c 2 5 7 4 3 6 9 h i /, U. W E / sl m d C S N 5 1 8 5 8 3 7 k n 2 3 3, 5 4 2 3 il

f. b

~ 5 Wa 8 y 8 ( n 7

7.,

6 5 1 1 o W E A4 5 0 6 2 3 1 5 i 1 i S t h t S N 2 3 3 5 4 2 3 r s a ,4e 2 2 8 8 5 3 Na o a N W 2 w h e S N h 4 7 2 6 5 5 0 4 / e t 2 2 3 4 3 1 3 /, i m t e u m 1 , o 5 y o 5 9 0 0 8 7 o a v. 1 a r E W 8 e /c l f S l 1 2 8 8 3 3 o i 1 l S N 1 2 2 3 2 1 2

r V-e i

= ul A Qb 8 2 8 2 8 7 9 / I %s E W to tI S N 3 8 0 2 8 9 8 n aT 1 1 2 3 1 1 p /e n k 1 /* ) v 1~0 a 4 5 8 4 9 0 '4 / 1 (7 E W S N 2 5 6 6 6 9 6 . /. 9 /) *4 s1 e E W 1 1 1 2 1 1 t - c o0 r / n5 o 6 6 2 4 5 /, /1 7 7 ~. 4 k [j F E W e 1 3 7 0 9 6 6 e i-[T C. n r 1 1 1 3 1 1 D. A dA ? 5 9 9 3 0 2r 5 1 E W so dTe /, / e. S tl S 1 5 8 9 4 6 6 E W 1 1 1 2 1 1 e e e r U / p 8 9 5 3

h. r 7

3 2 s r p

  • e a e E

U e /* R d e c N S 4 8 7 6 0 1 3 r ** o n yi 1 1 2 3 3 1 2 i v Gs7 /a w 0 r 6 7 8 8 4 5 2 e 3 tl f?/- l n S E t a n i S 6 1 7 3 1 2 5 e o r t S 1 2 2 4 3 1 2 m. t e i dh]C 7 6 9 4 G, a et 6 2 1 . r. a aeE N 5 8 6 3 8 0 0 1 3 1 2 3 4 4 2 3 BWf u l b a T x e 0 0 0 0 0 0 9 D o R rt) 0 0 0 0 0 0 a 1 r i A pl m 0, 3, 5, 2, 2, t e 0 W pa( R O A 3 4 5 9 2 6 v 1 1 A F T {l 4 ji! iq { i j'

Table 4.--Percentage of winds hv month, a t six al tituties from about 3.000 to 16,7~Osi~AiTWiEUi.- 000 m. averai ml. ~ .it.is ejl, pp_20-ypir' rEn~51[(,i,'('iO'- l['r/))). a t_Qu.i,1,1 ayn te.,_,Wy.h..,,,(W i n,,.s,,Al,o f t summ d 0 i..rvim,11';. Aii Forr.3 av.iilabl' from ths' fla tioral Clima tic Center [As, hey,i,l t FROM--- - N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNil NW l TOWARD--- 5 SSW SW WSW W WNW NW NNW N NNE NE ENE E ESE SE SSE JAN------ 3.4 1.4 0.7 0.5 0.5 0.2 0.5 1.0 2.7 6.8 12.5 16.9 18.4 15.2 11.9 7.0 F ut ---- -- 3.9 1.9 1.3 .6 .8 1.1 2.0 1.8 3.7 6.5 10.8 14.2 16.4 15.2 12.3 7.4 ~ Malt------ 4.5 21 1.1 .5 .9 .9 .9 1.5 4.3 U.4 12.2 14.2 15.5 ~12.7 1 2. 11 7.6 APR------ 4.2 2.7 2.1 1.4 1.2 1.3 1.6 2.6 4.8 7.0 11.9 13.4 14.8 12.2 11.3 7.6 ^ MAY------ 4.4 2.2 1.6 1.0 1.0 1.6 3.0 3.9 6.9 8.6 13.6 '15.0 13.0 10.1 7.7 6.0 . JUNE----- 3.7 2.8 2.3 1.7 1.4 1.5 1.7 2.8 6.0 9.0 13.9 14.9 13.4 10.0 8.6 6.2 JULY----- 3.1 1.9

1. 4' l.0

.9 .9 1.1 2.2 4.0 8.6 18.9 19.8 13.8 9.4 7.5 5.7 AUG------ 3.1 2,3 1.5 1.0 1.0 1.2 1.6 2.6 5.1 9.0 15.8 17.6 14.7 10.0 8.1 5.4 z SEPT----- 5.3 2.4 1.6 1.1 1.2 .8 1.2 2.2 3.2 7.9 12.2 12.7 14.7 14.7 11.3 7.7 OCT------ 2.2 1.4 .7 .4 .2 .2 .5 1.1 3.8 8.7 16.6 19.9 19.2 12.5 7.8 4.6 t10V------ 3.3 1.4 .5 .2 .4 .4 .8 1.7, 3.5 8.1 .13.9 17.0 20.2 14.0 11.3 5.1 DEC------ 3.1 1.2 .4 .3 .3 .3 .5 .9 3.2 8.8 14.4 17.4 18.5 14.4 10.5 6.0 AVERAGE-- 3.7 2.0 1.3 0.8 0.8 0.9 1.3.2.0 4.3.8.1 13.9 16.1 16.1 12.5 10.1 6.4 l Fr..,. cn,,cJe//, p. rz --c/ /J..e. Mus//,,e o us,' m 7 6, A/c.,NJ Hn -om/r & Khue. 1 S f. Al /c,,e 6 4 /e,,, w achi.,yAn, etC 6e t.yis-J Suu y C m s,~p N. s af /f*us./ a f;4 /< pea.s* 7C-4'9 / i

II C..~.C5CLO*10AL CAIE IN TEARS LJ u. O M M u k. n n. o a o ~ ~ q (e .o n a o e ~

  • =

e. c_n m_ c-N i..

g..

<.o, ' ' ' ' I -( ^ o w< z o 3s: = y 4 .~# g$ k" =c "J I Q P.d un W g a u O -4 m ) m a.: = s @2 ~ I

t

'. - w u-! T U .e, u - - w a z, V i e6 m, , 6 % =J o > as in., 1 s- >u g .sf e-N. o at me, W EB =4 2 o 'O 3 Z s CE .z 2 o, O. e a G t., eE E o. 's { .1 e c:: , o = = = u e. a.* a t, A. g 2_ O m i 5 a=c--00 5E 3,;s;s.

ps

= s z o. t--. Q ' 8 c= - zu u.o > g n. ~ 1 - --.4 - -- M O b neo I i 4 4 a egg -{. .= ooo ..m.,., s e. .,.,= c t..,+., ~ mo u. mw i u-o =s .=sas .g

( g y g

  • gg 2 as-

_,3

3g

.e.,o O o te, ,- 2.e,,,,, =.# hm em, N U e* . es te, he, O a - te. - s y\\ M La. c 4o J ^ =,, a. o e. e. e ' a,.g

2. = A e

," pz .- u o .l

    • M Usm= = *.,("

3-** b m ua ~ w u.0 m. O d; O N = ; :' _, 4.- "u. 0 l0 l ig" 5N i 0-

l l t I nI a aoI cc N .c h..sD a -= o

g w

O CMD ma E O ali -A

u. D d a

x,

5 o % q' J

~ = =

== i w 9 I m% % _a t A iI g ,(< < t, =N w ~ w 5 5 m t t O c'

5 o

e.* Y a ci {=- u u, v. .[ a i s 0- =, u. s t; OO O oi o g 3 b ;;* :' .m oc- - e 0 0 < ^, s O a. c= , A o, w o i i I t i I' ti1 't ! .c = o l, .f C l l z - '= 2._ c= a v= w z u- = = > > O :E C'- 4a z

i; w4

== =. ~. .c -u o 4 O s g_i= ' "ap 5,g c: . g' e x = ~ A O [i f O' 9 l O T w i i i ~ \\. ~, a a a g g a a a g a,,., o. e o o o o ~ = = ~ o TIME SEFCF.E FRE!ENT IN TEIRS D .}}

Retrieved from "https://kanterella.com/w/index.php?title=ML19331C892&oldid=4746130"